Light source device and projector

ABSTRACT

A light source device ( 10 ) has: a light-emitting tube ( 11 ) including a light-emitting portion ( 111 ) that emits a light beam through electrodes ( 114 ) and a pair of sealing portions ( 112, 113 ) provided on both sides of the light-emitting portion ( 111 ) and lead wires ( 200, 210 ) for making electrical continuity between the electrodes ( 114 ) and an external power source, the lead wires ( 200, 210 ) extending from the distal ends of the sealing portions ( 112, 113 ), respectively; and a reflector ( 12 ) having a concave reflecting surface ( 124 ) that emits, from the opening thereof, the light beam irradiated by the light-emitting tube ( 11 ) after aligning in a predetermined direction, in which the lead wire ( 200 ) extends from the sealing portion ( 112 ) on the light beam irradiation front side of the reflector ( 12 ) up to the opening end portion ( 125 ) of the reflector ( 12 ), the lead wire ( 200 ) having bent portions ( 221, 222, 223 ) in which the lead wire ( 200 ) is sequentially bent along the shape of the opening edge portion ( 125 ). The lead wire ( 200 ) is reliably fixed to the reflector ( 12 ) by the spring force between the bent portions ( 221, 222, 223 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light source device and a projector.

2. Description of Related Art

A Projector that modulates a light beam irradiated by a light source inaccordance with image information and projects an optical image in anenlarged manner has been widely used, together with a personal computer,for presentation in meetings, academic conferences, exhibitions, or thelike. In recent years, it has been used for at-home-movie-viewing.

As a light source device of the projector, a light source obtained byfitting a reflector to a light-emitting tube such as a metal halidelamp, a high-pressure mercury lamp, or halogen lamp is used. Anelectrical continuity between the light-emitting tube and an externalpower source is made by a lead wire welded to base caps of sealingportions disposed on both sides of the light-emitting tube.

As disclosed in Jpn. Pat. Laid-Open Publication No. 2003-132702 (seeFIG. 5 and the like), a light-emitting tube projects in a reflector. Inthis document, in order to draw a lead wire extending from the sealingportion on the projecting lead end out of the reflector and fix thedrawn out lead wire to the reflector, for example, a configuration inwhich the lead wire is inserted through a hole formed on the reflectorand the lead wire is fixed by a metal fitting at the hole portion hasbeen adopted.

In the case where a front glass for preventing the scatter of brokenpieces of the light-emitting tube upon burst of the same is provided, aconfiguration in which the lead wire is pinched between the edge portionof the front glass and opening edge portion of the reflector and fixedlybonded is employed to draw a lead wire extending from the sealingportion on the projecting lead end out of the reflector and fix thedrawn out lead wire to the reflector.

Further, to draw out and fix the lead wire, a configuration like a lightsource lamp unit 10′ shown in a sectional side view of FIG. 6 has beenemployed, for example. More specifically, in this light source lamp unit10′, a lead wire 200′ extends from a fastener 116 of a first sealingportion 112 toward an opening edge portion 125 of an ellipsoidalreflector 12 and further extends toward the outside of the ellipsoidalreflector 12 in such a manner to cross the peripheral edge of theopening edge portion 125. The drawn out lead wire 200′ extends along theperiphery of the ellipsoidal reflector 12 and is fixed.

In any of the above configuration, the lead wire is fixed to aconnection terminal to be connected to an external power source bywelding or the like, the connection terminal being disposed near thereflector.

However, in the configuration of the above document, a hole or the likemust be drilled in the reflector, decreasing an amount of the reflectedlight of the light source by the area corresponding to the hole. Thisreduces light utilization efficiency, thereby resulting in illuminationloss.

In the case where the sealing portion projects beyond the reflectoropening, the front glass cannot be provided depending on the shape ofthe light-emitting tube or reflector, in some cases. In this case, it isdifficult to fix the lead wire to the reflector. If the lead wire is notfixed to the reflector reliably, the lead wire has possibility offalling off from the welding portion when, for example, the lead wire isconnected to the connection terminal for an external power source.Specifically, when the lead wire may be pulled or pushed and contracted,a certain load is applied to the welding portion of the lead wire at thedistal end of the sealing portion, whereby the lead wire to come freefrom the welding portion, as often as not. In addition, the possibilitythat the light-emitting tube is broken or damaged by the applied loadoccurs to decrease built-in characteristics or reliability of the lightsource device. That is, there has been a need to realize a mechanism forreliably fix the lead wire even in the case where the front glass or thelie is not used.

In the wiring of the lead wire 200′ of the light source lamp unit 10′ asshown in FIG. 6, the lead wire 200′ is not fixed to the ellipsoidalreflector 12. Accordingly, the lead wire 200′ tends to be displaced atthe opening edge portion 125 of the ellipsoidal reflector 12, or tendsto slip off the opening edge portion 125, making it difficult to performthe wiring work of fixing the lead wire 200′ to a terminal blockFurther, during the wiring work, if the lead wire 200′ is pulled, orconversely, pushed and contracted, a certain load is applied to thewelding point on a fastener 116 of the distal end of the first sealingportion 112, with the result that the lead wire 200′ may slip off thefastener 116 or the light source lamp 11 may be broken or damaged.

SUMMARY OF THE INVENTION

Aspect of the present invention can provide a light source devicecapable of reliably fixing a lead wire without involving decrease inlight utilization efficiency and a projector provided with the lightsource device.

An exemplary a light source device according to an aspect of the presentinvention can include: a light-emitting tube including a light-emittingportion that emits a light beam through electrodes and a pair of sealingportions provided on both sides of the light-emitting portion and leadwires for making electrical continuity between the electrodes and anexternal power source, the lead wires extending from the distal ends ofthe sealing portions, respectively; and a reflector having a concavereflecting surface that irradiates, from the opening thereof, the lightbeam emitted by the light-emitting tube after being aligned in apredetermined direction. The light-emitting tube is provided such thatone of the pair of sealing portions projects toward the light beamirradiation front side of the reflector. The lead wire extending fromone of the sealing portions extends up to the opening edge portion ofthe reflector. The lead wire has a fold-down portion in which the leadwire extending up to the opening edge portion of the reflector is bentalong the shape of the opening edge portion.

According to the exemplary light source device, the lead wire extendingfrom one of the sealing portions that projects toward the light beamirradiation front side of the reflector up to the opening edge portionof the reflector has the fold-down portion in which the lead wire issequentially bent along the shape of the opening edge portion. With thisconfiguration, the opening edge portion is sandwiched by the fold-downportion to allow the lead wire to be easily and reliably fixed to thereflector. As a result, a satisfactory attachment intensity between thelead wire and the reflector can be obtained, so that the lead wire canbear an external force applied when the lead wire is pulled, orconversely, pushed and contracted during the wiring work in which thelead wires are routed or when the lead wire experiences a shock,preventing the lead wire from being slipped off or being displaced fromthe distal end of the sealing portion. This prevents the light-emittingtube from being broken or damaged even when the load caused by anexternal force is applied to the welding point at the distal end of thesealing portion. Therefore, it is possible to easily incorporate thelight source device in apparatuses such as a projector and to increasereliability thereof.

Further, a hole or the like for fixing the lead wire need not be formedin the reflector, avoiding a decrease in light utilization efficiency.

In the exemplary light source device it is preferable that the fold-downportion includes: a first bent portion in which the lead wire extendingfrom one of the sealing portions toward the inner circumferentialsurface of the opening edge portion is bent to the edge side of theopening edge portion of the reflector along the inner circumferentialsurface of the opening edge portion; a second bent portion in which thelead wire bent in the first bent portion is again bent along the endface of the opening edge portion; and a third bent portion in which thelead wire bent in the second bent portion is again bent along the outercircumferential surface of the reflector.

According to the exemplary light source device, the lead wire is foldeddown in such a manner to sandwich the opening edge portion of thereflector in the thickness direction thereof, so that a spring force ofthe fold-down portion acts both on the inner and outer circumferentialsurfaces of the reflector. With this configuration, the lead wire can befixed to the reflector more reliably. Further, spring forces of thefirst, second, and third bent portions are combined to act as resistanceagainst each other, contributing to reliable fixing between the leadwire and reflector.

In the exemplary light source device, it is preferable that thereflector be an ellipsoidal reflector having a ellipsoid of revolutionshaped reflecting surface. Furthermore, the light source device caninclude a sub-reflecting mirror that has a reflecting surface disposedopposite to the reflecting surface of the ellipsoidal reflector. Thereflecting surface of the sub-reflecting mirror can reflect the lightbeam irradiated by the light-emitting tube toward the ellipsoidalreflector.

According to the exemplary light source device, the light beamirradiated by the light-emitting portion and directed to the oppositeside of the reflecting surface of the ellipsoidal reflector is reflectedby the sub-reflecting mirror in the direction toward the ellipsoidalreflector. As a result, substantially all the light beams emitted by thelight-emitting portion are converged on the second focal positionsituated on the light beam irradiation front side by the ellipsoidalreflector, significantly increasing light utilization efficiency.

Further, by providing the sub-reflecting mirror, it is possible toreduce the opening diameter and dimension in the optical axis directionof the elliptical reflector realizing miniaturization of the lightsource device.

Since the sealing portion projects beyond the opening of the ellipsoidalreflector, it is hard to provide the front glass or the like forcovering the opening of the reflector and therefore, difficult to fixthe lead wire by inserting the lead wire between the edge portion of thefront glass and edge portion of the reflector. In the exemplary lightsource device, however, the lead wire is reliably fixed to the reflectorby the fold-down portion, as described above. Thus, the exemplary lightsource device can be very useful for the light source device having theellipsoidal reflector and sub-reflecting mirror and in which the sealingportion of the light-emitting tube projects beyond the opening of thereflector.

In the exemplary light source device, it is preferable that the leadwire including the fold-down portion be disposed in a plane includingthe center axis of the light beam irradiated by the reflector.

According to the exemplary light source device, the dimension in whichthe lead wire crosses the light path of the light beam irradiated by thereflector in the area between one of the sealing portions to the openingedge portion of the reflector is small so that the light shieldingamount by the lead wire can be reduced thereby contributing to anincrease in light utilization efficiency.

Incidentally, when the opening of the reflector is a circle, it ispreferable that the lead wire extend from the vicinity of the lightemitting portion in accordance with the radius position of the circle.Thus, the dimension in which the lead wire crosses the light path of thelight beam irradiated by the reflector can be made to be the shortest,so that the light shielding amount by the lead wire can further bereduced.

In the exemplary light source device, it is preferable that the leadwire including the fold-down portion further include a fourth bentportion in which the lead wire extending from one of the sealingportions toward the light emitting portion substantially along thecenter axis of the light beam irradiated by the reflector is bent to theopening end portion at the vicinity of the light emitting portion.

According to the exemplary light source device, the lead wire hardlyshields a light in the portion where the lead wire extends along thecenter axis direction of the light beam irradiated by the reflector.Further, the dimension in which the lead wire crosses the light path ofthe light beam irradiated by the reflector in the area between thevicinity of the light emitting portion and opening edge portion of thereflector is small, so that the light shielding amount by the lead wirecan be reduced as much as possible. This contributes to an increase inlight utilization efficiency.

Further, in the case where the ellipsoidal reflector that convergeslight beams on the second focal position of the ellipsoid situated onthe light beam irradiation front side relative to the opening of thereflector is used, the fourth bent portion is formed at the vicinity ofthe light emitting portion, so that it is possible to wire the lead wiresuch that the lead wire crosses the light beam at positions away fromthe second focal position. That is, by forming the fourth bent portionat the vicinity of the light emitting portion, it is possible to reducethe ratio of the area shielded by the lead wire that crosses theconverged light to the area of the cross section of the converged lightorthogonal to the irradiation direction. This is because the irradiatedlight beam from the reflector is converged toward the second focalposition of the ellipsoid, so that the cross sectional area thereoforthogonal to the light beam irradiation direction is decreased. Thisconfiguration can contribute to an increase in light utilizationefficiency.

An exemplary projector according to another aspect of the presentinvention can modulate the light beam irradiated by a light source inaccordance with image information to form an optical image and projectsthe optical image in an enlarged manner, the projector including theaforementioned light source device.

According to the exemplary projector, since the light source device hasthe aforementioned effects and advantages, the projector can obtain thesame effects and advantages as those of the light source device. Thatis, the light source device is excellent in light utilizationefficiency, so that the projector can form a bright and clear projectionimage. Further, the lead wire that makes electrical continuity betweenthe light-emitting portion and an external power source is reliablyfixed, easily incorporating the light source device in the projector andthereby increasing product reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view schematically showing an optical system of aprojector according to an exemplary embodiment of the present invention;

FIG. 2 is a perspective view showing a light source lamp unit accordingto the aforesaid exemplary embodiment;

FIG. 3 is a sectional side view of the light source lamp unit accordingto the aforesaid exemplary embodiment;

FIG. 4 is a sectional side view of the light source lamp unit andillustrating a pathway of a light beam irradiated by a light emittingsection according to the aforesaid exemplary embodiment;

FIG. 5 is a partial side sectional view of the light source lamp unitaccording to the exemplary embodiment; and

FIG. 6 is a partial side sectional view of a related art light sourcelamp unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An exemplary embodiment according to aspects of the present inventionwill be described below with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an optical system of a projector 1according to an exemplary embodiment. The projector 1 is an opticalapparatus that can form an optical image by modulating a light beamirradiated by a light source in accordance with image information andproject the optical image on a screen in an enlarged manner. Theprojector 1 can include a light source lamp unit 10 serving as a lightsource device, a integrator illumination optical system 20, a colorseparating optical system 30, a relay optical system 35, an opticaldevice 40 and a projection optical system 50. Optical elements of theoptical systems 20 through 35 can be housed with the positions thereofbeing adjusted within an optical components casing 2 where apredetermined illumination optical axis A is set.

The light source lamp unit 10 can irradiate the light beam emitted bythe light source lamp 11 after aligning in a predetermined direction toilluminate the optical device 40, and include a light source lamp 11, anellipsoidal reflector 12, a sub-reflecting mirror 13 and a parallelizingconcave lens 14, of which details will be described below.

The light beam emitted by the light source lamp 11 is irradiated as aconvergent light after the irradiating direction thereof being alignedtoward the front side of the optical device by the ellipsoidal reflector12, and is collimated by the parallelizing concave lens 14 to beirradiated to the integrator illumination optical system 20. The centeraxis of the light beam irradiated by the ellipsoidal reflector 12 iscoincident with the illumination optical axis A.

The integrator illumination optical system 20 can separate the lightbeam irradiated by the light source lamp unit 10 into a plurality ofsub-beams to equalize the in-plane illuminance of an illuminating area.The system 20 can include a first lens array 21, a second lens array 22,a PBS array 23, a condenser lens 24 and a reflection mirror 25.

The first lens array 21 functions as a light beam separating opticalelement that separates the light beam irradiated by the light sourcelamp 11 into a plurality of sub-beams, and has a plurality of smalllenses arranged in a matrix on a plane orthogonal to the illuminationoptical axis A, each profile of the respective small lenses beingarranged to be approximately similar to the profile of image formationareas of liquid crystal panels 42R, 42G, 42B of the optical device 40(described below).

The second lens array 22 is an optical element for condensing theplurality of sunbeams separated by the above first lens array 21, andhas a plurality of small lenses arranged in a matrix on a planeorthogonal to the illumination optical axis A as the first lens array21, however, each profile of the respective small lenses is not requiredto correspond with the profile of the image formation areas of theliquid crystal panels 42R, 42G, 42B since the second lens array 22 isfor condensing the light.

The PBS array 23 is a polarization conversion element that can convertpolarizing directions of the respective sub-beams separated by the firstlens array 21 into one linear polarized light of a predetermineddirection.

Though not shown, the PBS array 23 has an alternate arrangement of apolarization separating film and a reflection mirror both inclinedrelative to the illumination optical axis A. The polarization separatingfilm transmits either P-polarized light beam or S-polarized light beamcontained in the respective sub-beams whereas reflects the otherpolarized light beam. The reflected polarized light beam is bent by thereflection mirror to be irradiated in a direction to which thetransmitted polarized light beam is irradiated, i.e., in a directionalong the illumination optical axis A One of the irradiated P-polarizedlight beam and the S-polarized light beam is converted by a phase plateprovided on a light beam irradiation side of the PBS array 23 so thatthe polarizing directions of all polarized light beams are aligned. Withthe use of such PBS array 23, the light beam irradiated by the lightsource lamp 11 can be aligned as the polarized light beam in apredetermined direction, so that the utilization ratio of the light tobe used in the optical device 40 can be enhanced.

The condenser lens 24 can condense the plurality of sub-beams afterpassing the first lens array 21, the second lens array 22 and the PBSarray 23 to superpose the condensed light beam on the image formationareas of the liquid crystal panels 42R, 42G, 42B. Though the condenserlens 24 is a spherical lens in the exemplary embodiment, a light beamtransmitting area thereof having a flat light incident side and aspherical light irradiation side, an aspherical lens having ahyperboloidal light irradiation side may alternatively be used.

The light beam irradiated by the condenser lens 24 is bent by thereflection mirror 25 and irradiated to the color separating opticalsystem 30.

The color separating optical system 30 can have two dichroic mirrors 31and 32 and a reflection mirror 33, the dichroic mirrors 31 and 32separating the plurality of sub-beams irradiated by the integratorillumination optical system 20 into three color lights of red (R), green(G) and blue (B).

The dichroic mirrors 31 and 32 are optical elements each having a baseon which a wavelength-selection film that reflects a light beam of apredetermined wavelength and transmits a light beam of the otherwavelength is formed. The dichroic mirror 31 disposed on the upstream ofthe optical path is a mirror that transmits the red light and reflectsother color lights. The dichroic mirror 32 disposed on the downstream ofthe optical path is a mirror that reflects the green light and transmitsthe blue light.

The relay optical system 35 can have an incident-side lens 36, a relaylens 38, and reflection mirrors 37 and 39, and guide the blue lighttransmitted through the dichroic mirror 32 of the color separatingoptical system 30 to the optical device 40. Incidentally, the relayoptical system 35 is used for the optical path of the blue light inorder to avoid deterioration in the light utilization efficiency onaccount of light dispersion and the like caused by the longer length ofthe optical path of the blue light than the optical path of other colorlights. Though such arrangement is used in the exemplary embodimentbecause of the longer optical path of the blue light, a configurationmay be employed in which the optical path of the red light is lengthenedand the relay optical system 35 is used for the optical path of the redlight.

The red light separated by the above-described dichroic mirror 31 isbent by the reflection minor 33 and, subsequently, fed to the opticaldevice 40 through a field lens 41. The green light separated by thedichroic mirror 32 is directly fed to the optical device 40 through thefield lens 41. The blue light is condensed and bent by the lenses 36, 38and the reflection mirrors 37 and 39 of the relay optical system 35 tobe fed to the optical device 40 through the field lens 41. Incidentally,the field lenses 41 provided on the upstream of the optical path of therespective color lights of the optical device 40 are provided forconverting the respective sub-beams irradiated by the second lens array22 into light beams parallel to the illumination optical axis A.

The optical device 40 can form a color image by modulating the incidentlight beam in accordance with image information. The optical device 40can include liquid crystal panels 42 (42R, 42G, 42B) serving as anoptical modulator to be illuminated and a cross dichroic prism 43serving as a color-combining optical system. In addition, incident-sidepolarization plates 44 are respectively interposed between the fieldlenses 41 and the liquid crystal panels 42R, 42G, 42B, and, through notshown in the figure, irradiation-side polarization plates arerespectively interposed between the liquid crystal panels 42R, 42G, 42Band the cross dichroic prisms 43 so as to modulate the respectiveincident color lights through the incident-side polarization plates 44,the liquid crystal panels 42R, 42G, 42B and the irradiation-sidepolarization plates.

The liquid crystal panels 42R, 42G, 42B each have a pair oflight-transmissive glass substrates with liquid crystal as electro-opticmaterial sealed therebetween to modulate the polarizing direction of thepolarized light beam irradiated by each incident-side polarization plate44 in accordance with given image signal by using, for instance, apolysilicon TFT as a switching element. Each image formation area of theliquid crystal panels 42R, 42G, 42B for modulation has a rectangularshape having diagonal length of 0.7 inch, for example.

The cross dichroic prism 43 is an optical element that can combine theoptical image irradiated by the irradiation-side polarization plates andmodulated for each color light to form a color image. The cross dichroicprism 43 can contain four right-angle prisms mutually bonded in anapproximately planarly-viewed square. Dielectric multi-layer films canbe formed on the substantially X-shaped boundaries where the fourright-angle prisms are mutually bonded. One of the X-shaped dielectricmulti-layer films reflects the red light and the other one reflects theblue light, the red light and the blue light being bent by thedielectric multi-layer films and aligned with the advancement directionof the green light, so that the three color lights are combined.

The color image irradiated by the cross dichroic prism 43 is projectedby the projection optical system 50 in an enlarged manner to form alarge-size image on a screen (not shown).

FIG. 2 is a perspective view showing a light source lamp unit 10obliquely from behind.

The light source lamp unit 10 includes the aforementioned light sourcelamp 11, ellipsoidal reflector 12, sub-reflecting mirror 13, and theparallelizing concave lens 14. The light source lamp unit 10 furtherincludes a holder 16 that holds the parallelizing concave lens 14, and alamp housing 15.

The light source lamp 11 as a light-emitting tube has a silica glasstube with the central portion thereof being spherically bulged, thecentral portion being a light-emitting portion 111 and the portionsextending on both sides of the light-emitting portion 111 being a pairof sealing portions 112 (first sealing portion) and 113 (second sealingportion). In the exemplary embodiment, one of the sealing portions is afirst sealing portion 112 whereas the other one is a second sealingportion 113.

A metal halide lamp is used as the light source lamp 11 in the exemplaryembodiment Alternatively, however, various types of lamps such as adischarge type light-emitting tube including a high-pressure mercurylamp, a super high-pressure mercury lamp, and a xenon lamp, in whichdischarge light emission is made between a pair of electrodes, as wellas a halogen lamp may be used as the light source lamp 11.

FIG. 3 is a sectional side view of the light source lamp unit 10.

A pair of tungsten electrodes 114 spaced apart with each other in agiven interval, mercury, rare gas and a small amount of halogen aresealed in the light-emitting portion 111.

Metal foils 115 of molybdenum are inserted in the sealing portions 112and 113, respectively, the metal foils 115 being electrically connectedwith the electrodes 114 in the light-emitting portion 111. The metalfoils 115 are electrically connected to a lead wire 118 as an electrodeoutgoing line, the lead wire 118 extending to the outside of the lightsource lamp 11 from the sealing portions 112 and 113. The lead wire 118extending from the distal end of the first sealing portion 112 iselectrically connected to a lead wire 200 through the fastener 116. Thelead wire 118 extending from the distal end of the second sealingportion 113 is drawn to the outside through a base cap 117 so providedas to cover the distal end of the second sealing portion 113 andconnected to a lead wire 210. The lead wires 200 and 210 are connectedto the fastener 116 and base cap 117, respectively, by soldering or bypressure bonding. When a predetermined voltage is applied through thelead wires 200 and 210 from an external power source, arc discharge isgenerated between the pair of electrodes 114 and the light-emittingportion 111 emits a light beam.

As the lead wire 200 or 210, it is possible to use a linear element madeof metal such as nickel or gold, or an alloy of these materials havingthe rigidity corresponding to that of, e.g., a wire and capable ofmaintaining the shape of the bent portion. The base cap 117 is a memberfor protecting the second sealing portion 113. The base cap 117 may beomitted when there is no need to use it. The lead wire 118 to be drawnout from the distal end of the second sealing portion 113 may beelongated to be used as the lead wire 210. As the fastener 116, a ringsleeve or a pressure connection terminal can be adopted.

A heating wire 119 is wound around the second sealing portion 113 at thevicinity of the light-emitting portion 111. The heating wire 119 allowscurrent to flow therethrough to induce electric discharge between theelectrodes 114 at the starting time of the projector 1. The end portionof the heating wire 119 is welded to the fastener 116 at the distal endof the first sealing portion 112. Preheating effect of the heating wire119 on the light emitting portion 111 allows halogen cycle to start atan early time, thereby lighting the light source lamp 11 quickly.

The ellipsoidal reflector 12 is an integral molding consisting of silicaglass, sapphire glass, crystal, fluorite, YAG (Yttrium Aluminium Garnet,Y3A15O12), and the like including a neck portion 121 and a ellipsoid ofrevolution shaped reflecting portion 122 spreading from the neck portion121.

An insertion hole 123 is formed on the neck portion 121 at the middle,and the second sealing portion 113 is disposed in the insertion hole123.

A reflecting surface 124 is obtained by forming a dielectric multi-layerfilm on the surface of the reflecting portion 122. The reflectingsurface 124 serves as a cold mirror that reflects visible lights andtransmits infrared rays or ultraviolet rays. It is preferable that thereflecting surface 124 be formed by interlamination of a tantalumcompound and SiO2, or a hafnium compound and SiO2 using vacuumevaporation of a metal thin film, in view of heat resistance.

When the above light source lamp 11 is fixed to the ellipsoidalreflector 12, the second sealing portion 113 is inserted into theinsertion hole 123 of the ellipsoidal reflector 12, the light sourcelamp 11 is disposed so that the light-emission center between the pairof electrodes 114 in the light-emitting portion 111 is coincident with afirst focal position F1 of the ellipsoidal curve of the reflectingsurface 124, and a silica-alumina inorganic adhesive is filled insidethe insertion hole 123.

The dimension of the reflecting portion 122 in the direction of theillumination optical axis A is shorter than the length of the lightsource lamp 11, so that when the light source lamp 11 is fixed on theellipsoidal reflector 12 as described above, the first sealing portion112 of the light source lamp 11 projects from a light incident sideopening edge 125 of the ellipsoidal reflector 12.

The sub-reflecting mirror 13 is a reflecting member that is so disposedas to cover substantially the front half of the light-emitting portion111 of the light source lamp 11 and to face the reflecting surface 124of the ellipsoidal reflector 12. A reflecting surface 131 of thesub-reflecting mirror 13 is formed in a concave curve along thespherical surface of the light-emitting portion 111. The subreflectingmirror 13 is manufactured using, for example, a low-thermal expansionmaterial such as quartz or Neocerarn, or a high-thermal conductivematerial such as light-transmissive aluminum, sapphire, crystal,fluorite, YAG (Yttrium Aluminium Garnet, Y3A15O12). Like the ellipsoidalreflector 12, the reflecting surface 131 is formed of a dielectricmulti-layer film that reflects visible lights and transmits infraredrays or ultraviolet rays.

The parallelizing concave lens 14 is a member for collimating the lightbeam that has been emitted by the light source lamp 11 and reflected ina predetermined direction by the ellipsoidal reflector 12. A light beamincident side surface 141 is formed in an aspherical shape, e.g., ahyperboloidal shape and a light beam irradiation side surface 142thereof is formed in a flat shape.

Anti Reflection Coating (AR coating) is applied on the light beamincident side surface 141, and an ultraviolet protection film is formedon the light beam irradiation side surface 142, thereby enhancing lightutilization efficiency and preventing the optical components and thelike disposed on the downstream of the light source lamp unit 10 frombeing degraded due to influence of ultraviolet rays.

The holder 16 has a cylindrical shape formed in corresponding theopening edge portion 125 of the ellipsoidal reflector 12, the holder 16holding the outer circumferential edge of the parallelizing concave lens14 on the side opposite to the ellipsoidal reflector 12 and covering theopening of the ellipsoidal reflector 12. Further, holder 16 prevents thescatter of broken glass pieces or the like of the light source lamp 11upon burst of the lamp 11.

The holder 16 has a double structure of a holder main body 163 and alight absorption member 164 provided inside the holder main body 163.

The outside holder main body 163 is formed from an injection moldedsynthetic resin such as polyphenylene sulfide (PPS) or Vectra (LCP) andis constituted by a cylinder portion 161 and a holder portion 162, whichare integrally formed. The cylinder portion 161 has a cylindrical shapecorresponding to the shape of the opening edge portion 125 of theellipsoidal reflector 12, the cylinder portion 161 covering the lightsource lamp 11. The holder portion 162 is so formed as to seal the lightbeam irradiation side edge surface of the cylinder portion 161. Anopening 162A is formed at the holder portion 162, and the parallelizingconcave lens 14 is fitted to the opening 162A.

As the light absorption member 164 formed inside, various memberscapable of shielding the light towards the holder main body 163 from thelight source lamp as well as having low reflectance and thereby capableof absorbing light may be adopted. In order to reduce reflectance, whilehaving light shielding properties, a metal plate made of aluminum,magnesium, titanium, iron, copper, or an alloy of theses metals is usedas a base plate, and the inner surface of the base plate is subjected toblack alumite treatment or roughened by anti-corrosion processing,etching, or the like.

Although the reflectance of pure aluminum plate is about 80%, theapplication of the black alumite treatment reduces the reflectance notgreater than 20%. Thus, the light beam incident on the light absorptionmember 164 is reliably absorbed and shielded.

Corrosion resistance and light absorption properties of the lightabsorption member 164, which is based on the black alumite treatment,protects the holder main body 163, thereby preventing thermaldegradation and harmful gas such as siloxane from occurring.

Further, by means of the light absorption member 164, heat resistance ofthe entire holder 16 can be improved, so that a wide range of materialoptions of the holder main body 163 is available. Therefore, it ispossible to take action toward reduction in weight and cost orfacilitation of molding.

As shown in FIG. 2, the lamp housing 15 is an integral synthetic resinmolding with an L-shaped cross section, the lamp housing 15 having ahorizontal portion 151 and the vertical portion 152.

The vertical portion 152 is a part for positioning the ellipsoidalreflector 12 in the optical axis direction. An opening 153 is formed onthe vertical portion 152 along the light beam irradiation side edge ofthe ellipsoidal reflector 12. The opening edge portion 125 of theellipsoidal reflector 12 is fixed to the opening 153 by mechanicalpressing or adhesive. The holder 16 is also adhesively fixed to thevertical portion 152.

The horizontal portion 151 engages with the wall of the opticalcomponents casing 2 to conceal the light source lamp unit 10 within theoptical components casing 2 to prevent light leakage. The horizontalportion 151 includes a terminal block 154 having a pair of screws 154Aand 154B for electrically connecting the light source lamp 11 to anexternal power source.

Incidentally, projections and recesses are provided on the horizontalportion 151 and the vertical portion 152. The projections/recessesrespectively engage with recesses/projections formed inside the opticalcomponents casing 2 so that the light-emission center between theelectrodes 114 of the light source lamp 11 is located on theillumination optical axis A of the casing 2.

A description will next be given of the light beam irradiated by thelight-emitting portion 111 with reference to FIG. 4, which is asectional side view of the light source lamp unit 10. In FIG. 4, theheating wire 119 is omitted.

Of the light beam emitted from the light-emission center O of thelight-emitting portion 111, a light beam L1 directed to the ellipsoidalreflector 12 is reflected by the reflecting surface 124 of theellipsoidal reflector 12 to be irradiated toward a second focal positionF2.

A light beam L2 irradiated from the light-emission center O of thelight-emitting portion 111 and directed to the opposite side (light beamirradiation front side) of the ellipsoidal reflector 12 is reflected bythe reflecting surface 131 of the sub-reflecting mirror 13 in thedirection toward the ellipsoidal reflector 12, and again reflected bythe reflecting surface 124 of the ellipsoidal reflector 12 to beconverged on a second focal position F2. The light source lamp 11 isdisposed so that the light-emission center between the electrodes 114 ofthe light-emitting portion 111 is coincident with the first focalposition F1 of the ellipsoidal curve of the reflecting surface 124, sothat the light beam emitted from between the electrodes 114 can beconverged on the second focal position F2 by the ellipsoidal reflectorand thereby can be used as a point source.

As described above, the use of the sub-reflecting mirror 13 allows thelight beam irradiated by the light emitting portion 111 toward theopposite side (light beam irradiation front side) of the ellipsoidalreflector 12 to be reflected in such a direction to enter the reflectingsurface 124 of the ellipsoidal reflector 12. Therefore, substantiallyall the light beams irradiated by the light emitting portion 111 areconverged on the second focal position F2 of the ellipsoidal reflector12, thereby significantly increasing light utilization efficiency.

Since substantially all the light beams irradiated by the light emittingportion 111 can be converged on a certain position and then irradiatedas described above, a satisfactory light intensity can be obtainedirrespective of the surface area of the reflecting surface 124. As aresult, it is possible to reduce the dimension of the ellipsoidalreflector 12 in the direction of the optical axis and the openingdiameter to realize miniaturization of the light source lamp unit 10 andprojector 1, as well as to easily design the layout for incorporatingthe light source lamp unit 10 in the projector 1.

A description will next be given of the shape and wiring configurationof the lead wires 200 and 210 in the light source lamp unit 10, and afixing mechanism therefore.

In the exemplary embodiment, the lead wire 200 can be fixed to theellipsoidal reflector 12.

FIG. 5 is a sectional side view showing the light source lamp 11,ellipsoidal reflector 12, and sub-reflecting mirror 13 of the lightsource lamp unit 10. In FIG. 5, the lamp housing 15 and holder 16 areomitted.

The lead wire 210 extending from the second sealing portion 113 passesthrough the neck portion 121 and extends outside of the ellipsoidalreflector 12. The drawn out distal end of the lead wire 210 is welded tothe screw 154B of the terminal block 154 (FIG. 2).

Since the first sealing potion 112 projects from the opening of theellipsoidal reflector 12 and the opening of the ellipsoidal reflector 12is covered by the holder 16, the lead wire 200 extending from the firstsealing portion 112 passes through the opening edge portion 125 of theellipsoidal reflector 12 and is drawn out of the ellipsoidal reflector12. The dawn out distal end of the lead wire 200 is welded to the screw154A of the terminal block 154. In the exemplary embodiment, the leadwire 200 has bent portions that are formed by bending the lead wire 200.

In the plane including the center axis of the light beam irradiated bythe ellipsoidal reflector 12, the lead wire 200 extends along the sidesurface of the first sealing portion 112 from the fastener 116 of thefirst sealing portion 112 to the portion near the light emitting portion111, where the lead wire 200 is bent substantially at right angles to bedirected toward the opening edge portion 125 of the ellipsoidalreflector 12, assuming L-shape when viewed from the directionperpendicular to the center axis of the light beam irradiated by theellipsoidal reflector 12. Thus, a first straight portion 201 between thefastener 116 and light emitting portion 111, a second straight portion202 between the light emitting portion 111 and opening edge portion 125,and a fourth bent portion 203 between the first and second straightportions 201 and 202 are formed on the lead wire 200. When thereflecting surface 124 of the ellipsoidal reflector 12 viewed from thelight beam irradiation front side of the ellipsoidal reflector 12 alongthe illumination optical axis A, the lead wire 200 extends from thefirst sealing portion 112 to the opening edge portion 125 in a straightline. That is, the lead wire inside of the ellipsoidal reflector 12 iswired in a virtual plane including the center axis of the light beamirradiated by the ellipsoidal reflector 12.

The lead wire 200 extends along the illumination optical axis A in thefirst straight portion 201, so that the first straight portion 201 ofthe lead wire 200 hardly shields the light. Further, the lead wire 200extends substantially perpendicular to the illumination optical axis Ain the second straight portion 202, that is, the lead wire 200 crossesthe light path of the light beam irradiated by the ellipsoidal reflector12 by the most direct way, so that the light shielding amount by thelead wire 200 can be reduced as much as possible. Further, the secondstraight portion 202 extends up to the portion near the light emissionportion 111 and thereby the fourth bent portion 203 is formed at thevicinity of the light emitting portion 111, so that the second straightportion 202 starts at the position retreated from the second focalposition of the ellipsoidal reflector 12. By forming the fourth bentportion 203 nearer to the light emitting portion 111 as described above,it is possible to reduce the ratio of the area shielded by the secondstraight portion 202 that crosses the converged light to the area of thecross section of the converged light orthogonal to the irradiationdirection. This is because the irradiated light beam from theellipsoidal reflector 12 is converged toward the second focal positionof the ellipsoid, so that the cross sectional area thereof orthogonal tothe light beam irradiation direction is gradually decreased along withapproaching the second focal position. This configuration can contributeto an increase in light utilization efficiency and, therefore, brightand clear projection image can be expected.

The lead wire 200 is again bent in accordance with the shape of theopening edge portion 125 of the ellipsoidal reflector 12 in such amanner to sandwich the opening edge portion 125 in the thicknessdirection thereof. The shape of the bent portion is maintained as afold-down portion 220.

The lead wire 200 is bent in a sequential manner in the fold-downportion 220 along the shape of the opening edge portion 125 of theellipsoidal reflector 12. Thus, a first bent portion 221, a second bentportion 222, and a third bent portion 223 are formed in the fold-downportion 220 in the order mentioned from the inside of the ellipsoidalreflector 12, that is, the reflecting surface 124 side.

More specifically, in the first bent portion 221, the straight portion202 of the lead wire 200 extending from the portion near the lightemitting portion 111 and approaching to come close to the reflectingsurface 124 is bent to the edge side of the opening edge portion 125along the reflecting surface 124. In the second bent portion 222, thelead wire 200 is bent at the inner circumferential edge in the openingedge portion 125 to the outer circumferential edge side along the endface. In the third bent portion 223, the lead wire 200 is bent at theouter circumferential edge of the opening edge portion 125 along theouter circumferential surface of the ellipsoidal reflector 12. As aresult, the lead wire 200 assumes a hook-shape corresponding to theshape of the opening edge portion of the reflector. The spring forcebetween the bent portions 221, 222, and 223 biases the fold-down portion220 to sandwich the inner and outer circumferential surfaces of theellipsoid reflector 12.

The hook-shape is altered in accordance with the shape of the reflectoror light-emitting tube, wire configuration of the lead wire, or thelike. For example, in the case where the lead wire comes into contactwith the inner side surface of the reflector at substantially the centerportion, the lead wire may be bent to the opening inner circumferentialedge side at the contact portion, followed by being bent to the openingouter circumferential edge side at the opening inner circumferentialside edge.

Simply by hooking the fold-down portion 220 having a hook-shapecorresponding to the opening edge portion 125 of the ellipsoidalreflector 12 over the same, the lead wire 200 is reliably and easilyfixed to the ellipsoidal reflector 12 using the spring force between thebent portions 221, 222, and 223. As a result, the intensity of theattachment between the lead wire 200 and the opening edge portion 125 ofthe ellipsoidal reflector 12 is increased so that the lead wire 200 doesnot slip off the opening edge portion 125 of the ellipsoidal reflector12 even in the case where an external force is applied to the lead wire200 when the lead wire 200 is pulled, or conversely, pushed andcontracted during the wiring work in which the lead wires 200 and 210routed or fixed to the terminal block 154 or the like, or when the leadwire 200 experiences an external shock. As described above, thefold-down portion 220 of the lead wire 200 is reliably fixed to theopening edge portion 125 of the ellipsoidal reflector 12 even when anexternal force is applied to the lead wire 200 extending along the outercircumferential side of the ellipsoidal reflector 12, suppressinginfluence of the external force on the lead wire 200 extending in theinner circumferential side of the ellipsoidal reflector 12. Thisprevents the lead wire 200 from coming free of the welding point at thedistal end of the first sealing portion 112 and the light source lamp 11from being broken or damaged due to the load applied to the weldingpoint. Therefore, it is possible to easily perform the wiring work ofthe lead wire 200 and to increase reliability of the light source lampunit 10 and projector 1. Further, simply by forming the fold-downportion 220, the lead wire 200 can easily be drawn out without the needof forming a hole or the like in the ellipsoidal reflector 12. Thiseliminates inconvenience that light utilization efficiency is decreasedin proportion to the area of the hole.

The lead wire 200 is folded down in such a manner to sandwich theellipsoidal reflector 12 in the thickness direction thereof, so that thespring force between the bent portions 221, 222, and 223 acts both onthe inner and outer circumferential surfaces of the ellipsoidalreflector 12. As a result, the opening edge portion 125 of theellipsoidal reflector 12 is tightly sandwiched by the lead wire 200 bothfrom the inner and outer circumferential sides, so that the lead wire200 can be fixed to the ellipsoidal reflector 12 more reliably.

The first sealing portion 112 projects beyond the opening of theellipsoidal reflector 12 in the above configuration. Therefore, it isimpossible to provide the front glass or the like for the opening of theellipsoidal reflector 12 and therefore, impossible to fix the lead wire200 by inserting the lead wire 200 between the edge portion of the frontglass and opening edge portion 125 of the ellipsoidal reflector 12. Inthe exemplary embodiment, the lead wire 200 is reliably fixed to theellipsoidal reflector 12 by the aforementioned fold-down portion 220.Thus, the fixing mechanism of the lead wire 200 according to theexemplary embodiment can be very useful for the light source lamp unit10 having the ellipsoidal reflector 12 and sub-reflecting mirror 13 andin which the first sealing portion 112 projects beyond the opening ofthe ellipsoidal reflector 12.

The present invention is not limited to the above exemplary embodimentand can be changed and modified as in the following manner.

The shape and material of the light-emitting tube, reflector, lead wire,or sub-reflecting mirror, and the arrangement relationship between themare not limited to the above exemplary embodiment.

While the ellipsoidal reflector 12 is used as a reflector and theparallelizing concave lens 14 is used to collimate the light beam thathas been converged on the second focal position F2 in the aboveexemplary embodiment, the present invention is not limited to thisconfiguration. For example, a combination of a reflector having aparaboloidal reflecting surface and a convex lens that converges thelight beam that has been reflected by the reflector may be adopted. Thereflector has any shape as long as it serves as a convex lens.

Incidentally, in the above exemplary embodiment, even a configuration inwhich the sub-reflecting mirror 13 is not provided but the openingdiameter of the ellipsoidal reflector 12 and the dimension of the samein the optical axis direction are increased can attain the effect andadvantage of the present invention without problems.

In the above exemplary embodiment, while the first straight portion 201and second straight portion 202 that crosses the first straight portion201 are formed in the lead wire 200, the present invention is notlimited to such shape. For example, the lead wire is not bent at thevicinity of the light emitting portion, but may extend in a straightline from the distal end of the sealing portion to near the opening edgeportion of the reflector.

In short, the lead wire needs only to be bent at least two times alongthe shape of the opening edge portion of the reflector. With thisconfiguration, a spring force is caused in the two bent portions in thedirections different from each other, so that the lead wire can reliablybe fixed to the opening edge portion of the reflector in such a mannerthat the two bent portions press the opening edge portion.

Therefore the bending direction, bending angle, bending shape, bendingnumber, and the like of the lead wire are not limited to the aboveexemplary embodiment. For example, in the above exemplary embodiment, itis possible to additionally form a V-shape bent portion that goes andreturns along the inner circumferential surface of the opening edgeportion 125 of the ellipsoidal reflector 12. With this configuration,the opening edge portion 125 of the ellipsoidal reflector 12 is pressedby the V-shape bent portion and fold-down portion 220 with a strongerforce.

As the lead wire, it is possible to use a linear element or the likemade of metal such as nickel or gold, or an alloy of these materialshaving the rigidity corresponding to that of, e.g., a wire and capableof maintaining the shape of the bent portion.

Since the first sealing portion 112 projects beyond the opening of theellipsoidal reflector 12, it is difficult to cover the opening of theellipsoidal reflector 12 in the above exemplary embodiment. However, inthis case, a glass plate having a hole through which the first sealingportion 112 can be passed may be used to cover the opening of theellipsoidal reflector 12.

The present invention can be applied to the front type projector 1 thatprojects an image in a direction for observing a screen as described inthe above exemplary embodiment, as well as to a rear-type projector thatprojects an image in a direction opposite to the direction for observingthe screen.

While the preferred configuration, method, and the like for carrying outthe present invention are disclosed in the above descriptions, thepresent invention is not limited to this. That is, while the presentinvention has been illustrated and described in conjunction of aspecific preferred embodiment thereof, it is to be understood thatnumerous changes and modifications may be made to the shape, material,number, and other detailed configurations described in the aboveembodiment by those skilled in the art without departing from the spiritand scope of the present invention.

Therefore, the descriptions disclosed in the above that limit the shape,material, and the like are examples for making the present inventioneasier to understand and do not limit the present invention.Accordingly, descriptions made with names of the components in which apart of or all of the limitations such as the shape, material and thelike have been released can be regarded as the present invention.

The priority application Number JP2004-207791 upon which this patentapplication is based is hereby incorporated by reference.

1. A light source device, comprising: a light-emitting tube including alight-emitting portion that emits a light beam through electrodes and apair of sealing portions provided on both sides of the light-emittingportion and lead wires for making electrical continuity between theelectrodes and an external power source, the lead wires extending fromthe distal ends of the sealing portions, respectively; and a reflectorhaving a concave reflecting surface that irradiates, from an openingthereof, the light beam emitted by the light-emitting tube after beingaligned in a predetermined direction, wherein the light-emitting tube isprovided such that one of the pair of sealing portions projects towardthe light beam irradiation front side of the reflector, and the leadwire extending from one of the sealing portions extends up to an edgeportion of the opening of the reflector located on the side from whichthe light beam is irradiated, the lead wire having a fold-down portionin which the lead wire extending up to the opening edge portion of thereflector is bent along the shape of the opening edge portion.
 2. Thelight source device according to claim 1, wherein the fold-down portionincludes: a first bent portion in which the lead wire extending from oneof the sealing portions toward the inner circumferential surface of theopening edge portion is bent to the edge side of the opening edgeportion of the reflector along the inner circumferential surface of theopening edge portion; a second bent portion in which the lead wire bentin the first bent portion is again bent along the end face of theopening edge portion; and a third bent portion in which the lead wirebent in the second bent portion is again bent along the outercircumferential surface of the reflector.
 3. The light source deviceaccording to claim 1, wherein the lead wire including the fold-downportion is disposed in a plane including the center axis of the lightbeam irradiated by the reflector.
 4. The light source device accordingto claim 1, further comprising: a sub-reflecting mirror that has areflecting surface, the reflector is an ellipsoidal reflector having aellipsoid of revolution shapedreflecting surface, the reflecting surfaceof the sub-reflecting mirror is disposed opposite to the reflectingsurface of the ellipsoidal reflector, and the reflecting surface of thesub-reflecting mirror reflects the light beam irradiated by thelight-emitting tube toward the ellipsoidal reflector.
 5. The lightsource device according to claim 4, wherein the lead wire including thefold-down portion further includes a fourth bent portion in which thelead wire extending from one of the sealing portions toward near thelight emitting portion substantially along the center axis of the lightbeam irradiated by the reflector is bent to the opening end portion atthe vicinity of the light emitting portion.
 6. A projector thatmodulates the light beam irradiated by a light source in accordance withimage information to form an optical image and projects the opticalimage in an enlarged manner, comprising a light source device which hasa light-emitting tube including a light-emitting portion that emits alight beam through electrodes and a pair of sealing portions provided onboth sides of the light-emitting portion and lead wires for makingelectrical continuity between the electrodes and an external powersource, the lead wires extending from the distal ends of the sealingportions, respectively; and a reflector having a concave reflectingsurface that irradiates, from the opening thereof, the light beamemitted by the light-emitting tube after being aligned in apredetermined direction, wherein the light-emitting tube is providedsuch that one of the pair of sealing portions projects toward the lightbeam irradiation front side of the reflector, and the lead wireextending from one of the sealing portions extends up to an edge portionof the opening of the reflector located on the side from which the lightbeam is irradiated, the lead wire having a fold-down portion in whichthe lead wire extending up to the opening edge portion of the reflectoris bent along the shape of the opening edge portion.
 7. The projectoraccording to claim 6, wherein the fold-down portion includes: a firstbent portion in which the lead wire extending from one of the sealingportions toward the inner circumferential surface of the opening edgeportion is bent to the edge side of the opening edge portion of thereflector along the inner circumferential surface of the opening edgeportion; a second bent portion in which the lead wire bent in the firstbent portion is again bent along the end face of the opening edgeportion; and a third bent portion in which the lead wire bent in thesecond bent portion is again bent along the outer circumferentialsurface of the reflector.
 8. The projector according to claim 6, whereinthe lead wire including the fold-down portion is disposed in a planeincluding the center axis of the light beam irradiated by the reflector.9. The projector according to claim 6, further comprising: asub-reflecting mirror that has a reflecting surface, the reflector is anellipsoidal reflector having a ellipsoid of revolution shaped reflectingsurface, the reflecting surface of the sub-reflecting mirror is disposedopposite to the reflecting surface of the ellipsoidal reflector, and thereflecting surface of the sub-reflecting mirror reflects the light beamirradiated by the light-emitting tube toward the ellipsoidal reflector.10. The projector according to claim 9, wherein the lead wire includingthe fold-down portion further includes a fourth bent portion in whichthe lead wire extending from one of the sealing portions toward near thelight emitting portion substantially along the center axis of the lightbeam irradiated by the reflector is bent to the opening end portion atthe vicinity of the light emitting portion.